wifi连接丢失时如何防止App崩溃

Question

寻找了很多建议，但找不到适合我的建议。

我正在执行网络服务调用：

/**
 * Making service call
 */
private String makeWebServiceCall(String urlAddress, int requestMethod, String params) {
    String response = "";
    HttpURLConnection urlConnection;
    try {
        urlConnection = getConnection(urlAddress, requestMethod);
        urlConnection.connect();
        writeParameters(urlConnection, params);
        response = convertStreamToString(urlConnection);
        Log.d("makeWebServiceCall : ", response);
    } catch (Exception e) {
        //response = "Failed to connect";
        Log.d("makeWebServiceCall ", response);
        Log.e(TAG, "IOException parsing to json", e);
    }
        return response;
}

private HttpURLConnection getConnection(String urlAddress, int requestMethod) throws IOException {


    URL url = new URL(urlAddress);
    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
    try {
        urlConnection.setReadTimeout(3000);
        urlConnection.setConnectTimeout(3000);
        urlConnection.setDoInput(true);
        urlConnection.setDoOutput(true);

        if (requestMethod == POST) {
            urlConnection.setRequestMethod("POST");
        } else if (requestMethod == GET) {
            urlConnection.setRequestMethod("GET");
        }

    } catch (Exception e) {
        new AlertDialog.Builder(context)
                .setIcon(R.drawable.launcher_logo)
                .setTitle("No internet connection")
                .setMessage("Please turn on mobile data");
    }

    return urlConnection;
}

private String writeParameters(HttpURLConnection connection, String jsonString) throws IOException {

    if (!TextUtils.isEmpty(jsonString)) {

        OutputStream outputstream = connection.getOutputStream();
        BufferedWriter bufferedWriter = new BufferedWriter(
                new OutputStreamWriter(outputstream, "UTF-8"));

        bufferedWriter.write(jsonString);

        bufferedWriter.flush();
        bufferedWriter.close();
        outputstream.close();

        return jsonString;

    } else {
        return "JSONString is empty";
    }
}

private String convertStreamToString(HttpURLConnection connection) throws IOException {
    String responseLine = "";

    int responseCode = connection.getResponseCode();

    if (responseCode == HttpsURLConnection.HTTP_OK) {
        String line;

        BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        while ((line = br.readLine()) != null) {
            responseLine += line;
        }
    }
    return responseLine;
}

当连接丢失时，我收到异常“IOException parsing to json”：

日志猫：

E/RestClient：IOException 解析为 json java.net.SocketTimeoutException：在 libcore.io.IoBridge.connectErrno(IoBridge.java:169) 的 libcore.io.IoBridge 3000 毫秒后无法连接到 /192.168.1.1（端口 80）。 connect(IoBridge.java:122) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:183) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:452) at java.net.Socket.connect(Socket.java) :884) 在 com.android.okhttp.internal.Platform.connectSocket(Platform.java:117) 在 com.android.okhttp.internal.http.SocketConnector.connectRawSocket(SocketConnector.java:160) 在 com.android.okhttp。 internal.http.SocketConnector.connectCleartext(SocketConnector.java:67) at com.android.okhttp.Connection.connect(Connection.java:152) at com.android.okhttp.Connection.connectAndSetOwner(Connection.java:185) at com .android.okhttp.OkHttpClient$1.connectAndSetOwner(OkHttpClient.java:128) 在 com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:341) 在 com.android.okhttp.internal.http。 HttpEngine.connect(HttpEngine.java:330) 在 com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:248) 在 com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java: 437) 在 com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:114) 在 com.example.pc.teltonikaapplication.JSon.RestClient.makeWebServiceCall(RestClient.java:118) 在 com.example.pc .teltonikaapplication.JSon.RestClient.deviceDownloadUploadData(RestClient.java:73) 在 com.example.pc.teltonikaapplication.fragment.MainWindowFragment.doInBackground(MainWindowFragment.java:107) 在 com.example.pc.teltonikaapplication.fragment.MainWindowFragment.doInBackground (MainWindowFragment.java:28) 在 com.example.pc.teltonikaapplication.util.Task.doInBackground(Task.java:27) 在 android.os.AsyncTask$2.call(AsyncTask.java:295) 在 java.util.concurrent .FutureTask.run(FutureTask.java:237) 在 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113) ) 在 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588) 在 java.lang.Thread.run(Thread.java:818)

一切看起来都很好，如果没有连接异常被捕获，但是如何处理崩溃以防止它发生？

Answer 1

一旦我在我的应用程序中实施了检查，看看是否有任何互联网连接。 你可以看看这个——

public class ConnectionDetector {

private Context context;

public ConnectionDetector(Context cont){
this.context = cont;
}

public boolean isConnectingToInternet(){
ConnectivityManager connectivity = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivity != null)
{
NetworkInfo[] info = connectivity.getAllNetworkInfo();
if (info != null) {
    for (int i = 0; i < info.length; i++) {
        if (info[i].getState() == NetworkInfo.State.CONNECTED) {
            return true;
        }
    }
}

}
 return false;
}
}

您可以在OnCreate方法中初始化此类的对象。

最后在你上传文件之前调用这个类的方法。

Boolean isInternetConnected = cd.isConnectingToInternet();
if (isInternetConnected)
{
    //perform your job here.
}

希望这可以帮助。